/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Text;
using Spring.Util;

namespace Spring.Core.IO;

/// <summary>
/// Holder that combines <see cref="IResource" /> with a specific encoding to be used for reading
/// from the resource
/// </summary>
/// <author>Juergen Hoeller</author>
/// <author>Erich Eichinger (.NET)</author>
public class EncodedResource
{
    private readonly IResource resource;
    private readonly Encoding encoding;
    private readonly bool autoDetectEncoding;

    /// <summary>
    /// Create an encoded resource, autodetecting the encoding from the resource stream.
    /// </summary>
    /// <param name="resource"></param>
    public EncodedResource(IResource resource)
        : this(resource, null, true)
    {
        // noop
    }

    /// <summary>
    /// Create an encoded resource, autodetecting the encoding from the resource stream.
    /// </summary>
    /// <param name="resource">the resource to read from. Must not be <c>null</c></param>
    /// <param name="autoDetectEncoding">whether to autoDetect encoding from byte-order marks (<see cref="M:StreamReader(Stream, Encoding, bool)"/>)</param>
    public EncodedResource(IResource resource, bool autoDetectEncoding)
        : this(resource, null, autoDetectEncoding)
    {
        // noop
    }

    /// <summary>
    /// Create an encoded resource using the specified encoding.
    /// </summary>
    /// <param name="resource">the resource to read from. Must not be <c>null</c></param>
    /// <param name="encoding">the encoding to use. If <c>null</c>, encoding will be autodetected.</param>
    /// <param name="autoDetectEncoding">whether to autoDetect encoding from byte-order marks (<see cref="M:StreamReader(Stream, Encoding, bool)"/>)</param>
    public EncodedResource(IResource resource, Encoding encoding, bool autoDetectEncoding)
    {
        AssertUtils.ArgumentNotNull(resource, "resource");
        this.resource = resource;
        this.encoding = encoding;
        this.autoDetectEncoding = autoDetectEncoding;
    }

    /// <summary>
    /// Get the underlying resource
    /// </summary>
    public IResource Resource
    {
        get { return resource; }
    }

    /// <summary>
    /// Get the encoding to use for reading, if any. May be <c>null</c>
    /// </summary>
    public Encoding Encoding
    {
        get { return encoding; }
    }

    /// <summary>
    /// whether to autoDetect encoding from byte-order marks (<see cref="M:StreamReader(Stream, Encoding, bool)"/>)
    /// </summary>
    public bool AutoDetectEncoding
    {
        get { return autoDetectEncoding; }
    }

    /// <summary>
    ///
    /// </summary>
    /// <returns></returns>
    public TextReader OpenReader()
    {
        if (this.encoding != null)
        {
            return new StreamReader(this.resource.InputStream, this.encoding, autoDetectEncoding);
        }

        return new StreamReader(this.resource.InputStream, autoDetectEncoding);
    }

    /// <summary>
    /// Determine whether <paramref name="obj"/> equals this instance.
    /// </summary>
    /// <returns>
    /// <c>true</c> if obj is an <see cref="EncodedResource"/> and both
    /// , <see cref="Resource"/> and <see cref="Encoding"/> are equal.
    /// </returns>
    public override bool Equals(object obj)
    {
        if (obj == this) return true;
        if (!(obj is EncodedResource)) return false;

        EncodedResource other = (EncodedResource) obj;
        return object.Equals(this.resource, other.resource)
               && object.Equals(this.encoding, other.encoding);
    }

    /// <summary>
    /// Calculate the unique hash code for this instance.
    /// </summary>
    /// <returns></returns>
    public override int GetHashCode()
    {
        return this.resource.GetHashCode();
    }

    /// <summary>
    /// Get a textual description of the resource.
    /// </summary>
    public override string ToString()
    {
        return this.resource.ToString();
    }
}
